Hot and Cold describe the nature of a pattern, and their associated symptoms depend on whether they are combined with a Excess or Deficient condition.
Excess-Heat can be external (as in Wind-Heat) or internal. The symptoms of invasion of Wind-Heat have already been described in the page on the Interior. Excess-Heat (whether external or internal) is a manifestation of Excessive Yang.
The main symptoms of Excess-Heat in an Internal condition are thirst, a feeling of heat, some mental restlessness, red face, dry stools, scanty dark urine, a Rapid-Full pulse, and a Red tongue with yellow coating.
Beyond these, it is difficult to generalize as other symptoms will depend on the organ affected. Aside from the above symptoms, there are other diagnostic guides which indicate Heat. Any raised, red skin eruption which feels hot indicates Heat. As for pain, any burning sensation indicates Heat: for example, the burning sensation of cystitis, or a burning feeling in the stomach. Any loss of blood, with large quantities of dark-red blood, indicates Heat in the Blood. As far as the mind is concerned, any condition of extreme restlessness or manic behaviour indicates Heat in the Heart.
Internal Excess-Heat may derive directly from the excessive consumption of hot-energy foods (e.g. red meats, spices and alcohol) or, indirectly, from emotional stress.
In fact, emotional stress tends to cause Qi stagnation in its early stages; if Qi stagnates for some time, it usually gives rise to some Heat. With further passage of time, Heat may turn into Fire. Finally, Internal Excess-Heat may also derive from the transformation of a pathogenic factor which penetrates the Interior and turns into Heat as it does so.
From the Yin–Yang point of view, Deficient-Heat arises from a Deficiency of Yin. If the Yin energy is deficient for a long period of time, the Yin is consumed and the Yang is relatively in Excess. Please note that Yin may be deficient for years before giving rise to Deficient-Heat. Therefore, Deficient-Heat always derives from Yin deficiency but a patient can very much suffer from a Yin Deficiency without Deficient-Heat. The tongue will show the difference clearly: in Yin deficiency, the tongue lacks a coating but it has a normal color; in Yin deficiency with Deficient-Heat, the tongue lacks a coating and is red.
The main general manifestations of Deficient-Heat are a feeling of heat at the end of the day, a dry mouth with desire to drink in small sips, a dry throat at night, night sweating, a feeling of heat in the chest and palms and soles (also called ‘five-palm heat’), dry stools, scanty dark urine, a Floating-Empty and Rapid pulse and a Red tongue without coating.
Again, these are only the general symptoms and signs; others depend on which Organ is mostly affected. Deficient-Heat frequently arises from deficiency of Kidney-Yin. Because Kidney-Yin is the foundation for all the Yin energies of the body, when this is deficient it can affect the Yin of the Liver, Heart and Lungs. A long-standing deficiency of Yin in any of these organs can give rise to Deficient-Heat manifesting with various symptoms, such as mental restlessness and insomnia when Heart-Yin is deficient, irritability and headaches when Liver-Yin is deficient and dry cough when Lungs-Yin is deficient.
Aside from these manifestations, from a mental–emotional point of view Deficient-Heat can often be lead to a feeling of mental restlessness, fidgeting and vague anxiety. The patient feels that something is wrong but is unable to describe what or how. Deficient-Heat restlessness is quite different from that of Excess-Heat and one can almost visually perceive the Emptiness underlying the Heat.
In practice, it is important to differentiate Excess-Heat from Deficient-Heat as the treatment method in the former case is to clear the Heat, while in the latter case it is to nourish Yin.
It is worth noting also that Deficient-Heat is no less ‘real’ than Full-Heat. The term ‘Deficient’ in ‘Deficient-Heat’ may give the false impression that this is not ‘real’ Heat: in fact, Deficient-Heat produces as much heat as Excess-Heat, albeit in different forms.
Deficient-Heat derives from Yin deficiency: therefore the causes of Deficient-Heat are the same as those that cause Yin deficiency. These causes are:
The most common situation in which there are manifestations of both Heat and Cold is when these patterns simply coexist. This is an extremely common situation in practice. For example, it is common for a person to suffer from Kidney-Yang deficiency (hence Deficient-Cold in the Kidneys) and Damp-Heat in the Bladder, or Spleen-Yang deficiency and Liver-Fire.
We should therefore not be surprised when we observe contradictory Hot and Cold symptoms in practice: in most cases, they are due to the coexistence of Hot and Cold patterns. To return to the above example, if a patient suffers from Spleen-Yang deficiency, he or she may feel generally cold but have a red face and thirst.
In some cases there may be contradictory Hot and Cold signs and symptoms, one of them being due to a ‘false’ appearance. This usually only happens in extreme conditions and is quite rare. It is important not to confuse this phenomenon with common situations when Heat and Cold are simply combined, as described right above.
For example, it is perfectly possible for someone to have a condition of Damp-Heat in the Bladder and Cold in the Spleen. This is simply a combination of Hot and Cold signs in two different organs, and does not fall under the category of False Heat and True Cold or vice versa.
In cases of False Heat and False Cold, tongue diagnosis shows its most useful aspect as the tongue-body colour nearly always reflects the true condition. If the tongue-body colour is Red it indicates Heat, if it is Pale it indicates Cold.
In some cases there is Heat above (as Heat tends to rise) and Cold below. The manifestations of this situation might be thirst, irritability, sour regurgitation, bitter taste, mouth ulcers (manifestations of Heat above), loose stools, stomach rumbles and profuse pale urine (manifestations of Cold below).
The symptoms and signs would include a fever with aversion to cold, no sweating, a headache and stiff neck, aches throughout the body (manifestations of exterior Cold), irritability and thirst (manifestations of interior Heat).
This situation also occurs in attacks of Latent Heat combined with a new invasion of Wind-Cold. According to the theory of Warm diseases a person can be attacked by Cold in wintertime without developing any manifestations of it. The Cold can lie dormant in the Interior and change into Heat. In the Spring, with the rising of Yang energy, the interior Heat may be pulled towards the Exterior, especially in combination with a new attack of Wind-Cold. Because of this, the person would have symptoms and signs of an attack of Wind-Cold, but also signs of interior Heat such as a thirst, irritability and a rapid pulse.
This situation simply occurs when a person with a Cold condition is attacked by exterior Wind-Heat. There will therefore be some symptoms of exterior invasion of Wind-Heat (such as a fever with aversion to cold, a sore throat, thirst, a headache and a Floating-Rapid pulse) and some symptoms of interior Cold (such as loose stools, chilliness and profuse pale urine).